1. Field of the Invention
This invention relates generally to stop-cock valves used with fluid delivery sets. More specifically, this invention relates to a stop-cock valve having an improved anti-free flow design which can be sterilized by gas sterilization methods.
2. Description of the Prior Art
It is well known in the prior art to introduce fluids to a patient, either intravenously or enterally for the purposes of medication or alimentation. Such fluid delivery systems typically include one or more flexible plastic tubes connected to one or more containers of fluid to be administered to the patient. In many instances, it is desirable to switch from one fluid container to another during patient administration either for purposes of changing the fluid being administered, or to flush the fluid delivery set to prevent blockage of the fluid line from occurring during use. To accommodate the delivery of fluid from a plurality of containers to a patient, it is well known to provide the fluid delivery set with a stop-cock valve which allows switching from one fluid container to another. Such valves normally employ a rotatable stem which allows the operator thereof to choose which fluid container is placed in fluid flow communication with the patient by rotation of the stem relative to the valve.
One of the primary difficulties with this type of valve is that it is not always apparent to the operator which fluid flow container is in fluid flow communication with the patient. Also, in the particular instance where the operator is preparing the fluid delivery set for initial use with a patient, it is often difficult to ensure that the valve has remained closed in order to prevent accidental premature free-flow of fluid during preparation of the delivery set. Another common difficulty with stop-cock valves of this type is that of ensuring that complete sterilization of the fluid flow channels within the rotating stem thereof occurs during gas sterilization. Since an open gas flow passage must be available through the stem in order to ensure proper gas sterilization of the internal flow passages therethrough, it is necessary to be able to ensure that the rotating stem is always in the proper position to allow free-flow of gas therethrough when the valve is being sterilized.
Accordingly, there is a need in the prior art to develop a stop-cock type valve which allows for simple and immediate visual and/or tactile indication of the position of the rotatable stem in the valve. Further, there is a need in the art for a stop-cock valve which ensures that the rotatable stem thereof remains in the closed position prior to initial use in order to avoid accidental free flow of fluid therethrough during setup. Also there is a need in the art for a stop-cock valve which is gas sterilizeable with complete assurance that the sterilizing gas has access to the flow passages within the rotating stem. There is also a need for a valve which never allows fluid flow connection to occur between inlet ports, regardless of the position of the valve stem thereof so as to prevent intermixing of solutions in the fluid containers which may be attached to the inlet ports.